Automatic zigzaggers with adjustable drive levers



J. P; ENOS Oct. 27, 1959 AUTOMATIC ZIGZAGGERS WITH ADJUSTABLE DRIVE LEVERS Filed July 8. 1958 INVENTOR John P Enos ATTORNEY Fig.3

WI TNESS %'77 2,910,025 Patented Oct. 27, 19 59 lice AUTOMATIC ZIGZAGGERS WITH ADJUSTABLE DRIVE LEVERS John P. Enos, Union, N.J., assign'or to The Singer Manufacturing Company, Elizabeth, N.J., a corporation of New Jersey Application July 8, 1958, Serial No. 747,133

2 Claims. (Cl. 112160) This invention relates to needle bar operated attachments for sewing machines and more particularly to an improved needle bar operated drive lever for a sewing machine attachment. 4

It is an object of this invention to provide an improved sewing machine attachment drive lever which may be adjusted quickly and easily to accommodate any one of a variety of sewing machines having different needle bar stroke and needle bar timing.

Another object of this invention is to provide a clamp screw for securing the attachment drive lever in selected position of adjustment, which clamp screw is threaded for its entire length into the fulcrum stud for the attachment drive lever.

It is also an object of this invention to provide an attachment drive lever of the above character with indicia for visually indicating the proper adjustment for one or more of the most prevalent types of sewing machines.

The preferred form of this invention is illustrated in the accompanying drawings in which:

Fig. 1 represents a top plan view of a needle bar operated sewing machine attachment having an attachment drive lever built in accordance with this invention,

Fig. 2 represents a side elevational view of the attachment illustrated in Fig. 1, and

Fig. 3 is a cross sectional view of a portion of the attachment drive lever taken substantially along line 3-3 of Fig. 2.

The drawings illustrate a zigzag attachment for a sewing machine, which attachment is actuated by the reciprocatory sewing machine needle bar 11 and the motion thus derived is utilized by the attachment to jog a work fabric transversely of the needle bar axis to cause the formation of zigzag stitches. With exception of the needle bar operated drive lever assembly, this attachment may be constructed in accordance with my United States patent application Serial No. 533,942, filed September 13, 1955, now Patent No. 2,861,528, granted November 25, 1958, to which reference may be had for a complete description thereof.

Referring to the drawings, 12 indicates an attachment frame formed with spaced upstanding ears 13 between which is riveted a block 14 formed with a seat 15 for reception of the sewing machine presser bar 16. A fastening screw 17 is used to secure the attachment frame to the sewing machine presser bar.

Carried beneath the attachment frame is a work jogging foot 18 which is vibrated transversely of the needle bar axis by mechanism in the attachment, such mechanism being described in the above mentioned patent application Serial No. 533,942. The motion necessary to drive the attachment mechanism is derived from the movement of the sewing machine needle bar 11 by way of an oscillatory drive lever arm 19 fixedly secured to a fulcrum pin 20 journaled in the spaced frame ears 13 and formed at its free extremity with bifurcations 21 embracing the needle clamp thumb screw 22 on the needle bar.

Pivoted to the drive lever arm 19 on a shouldered pin or rivet 23 spaced beneath the axis of the fulcrum pin 20 is a lever arm 24 which at its free extremity is pivoted as at 25 to a link 26 which transmits motion to the attachment actuating mechanism.

The lever arm 24 is formed with an arcuate slot 27 having its center of curvature coincident with the axis of the rivet 23 upon which the lever arm 24 is pivoted to the driving lever arm 19. A clamp screw 28 passes through the arcuate slot 27 and is threaded into the fulcrum pin 20 for the purpose of securing the lever arm 24 to the driving lever arm 19 in selected angular relationship within the range of adjustment provided by the arcuate slot 27.

The lever arm 24 is preferably formed with an upstanding finger grip 29 to facilitate angular adjustment of the lever arm with respect to the driving lever arm. The lever arm 24 is also formed with an indicating pointer 30 which cooperates with indicia 31 on the driving lever arm to provide a visual indication of the position of adjustment of the lever arm 24. Preferably, the indicia 31 correspond to the proper position of adjustment for one or more of the most prevalent types of sewing machines.

One advantage of having the rivet 23 upon which the lever arm 24 is turned located at a point spaced from and beneath the axis of the fulcrum pin 20 is that the angular adjustment of the leverarm 24 is less sensitive than if the turning of the lever arm occurred on an axis coincident with that of the fulcrum pin 20 of the driving lever arm.

Another advantage of the location of the rivet 23 is that the clamp screw 28 may be located substantially coincident with the axis of the fulcrum pin 20 which provides a solid metallic element into which the clamp screw 28 may be threaded for its entire length. This arrangement provides for a more durable clamping arrangement which will not loosen readily nor strip the threads of the clamp screw. Also, since the fulcrum pin 20 is produced on an automatic screw machine, the addition of the threaded hole axially of the pin can be obtained at substantially no increase in the cost of manufacture of the fulcrum pin.

Having thus set forth the nature of this invention, what I claim herein is:

1. In a needle bar operated sewing machine attachment, a drive lever assembly comprising, a drive lever arm adapted to be oscillated by the needle bar, means pivoting said driving lever arm to said attachment including a fulcrum pin secured to said driving lever arm and journaled in said attachment, a second lever arm adapted to transmit motion from said driving lever arm to said attachment, means pivoting said second lever arm to said driving lever arm about an axis spaced from said fulcrum pin,

and means for clamping said lever arms in selected angular position including a clamp screw threaded into said fulcrum pin, said second lever arm formed with an arcuate slot embracing said clamp screw and having a center of curvature coincident with said means pivoting said second lever arm to said driving lever arm.

2. In a needle bar operated sewing machine attachment, a drive lever assembly comprising, a driving lever arm adapted to be oscillated by the needle bar, means pivoting said driving lever arm to said attachment including a fulcrum pin secured to said driving lever arm and journaled in said attachment, a second lever arm adapted to trans mit motion from said driving lever arm to said attachcenter of curvature coincident with said means pivoting said second lever arm to said driving leverarm, hand a finger grip formed on said second lever arm above said fulcrum pin.

References Cited in the file of this patent UNITED STATES PATENTS Gilbert l Dec. 15, 1885 Morin Dec. 22, 1908 Karle Dec. 8, 1936 

